Polybutylene terephthalate (also referred to as “PBT”) is used in a wide variety of applications. For example, blends of PBT with polyamide can have improved heat resistance and water absorption resistance. The expansion of the field of use of PBT-polymer blends, however, has brought about an ever-increasing demand for an improvement in the performance of such blends, in particular improved toughness, impact resistance, heat resistance, and alkali resistance. In addition, even when PBT and a polyamide are blended and melt-mixed, it can be difficult to attain a homogeneous dispersion. In injection-molded articles in particular, the surface layer of the articles have a laminar structure, such that severe peeling can occur at the surface.
Another drawback of PBT-polymer blends is that such blends generally are not made from recycle sources of PBT. This is due at least in part to the lack of availability of PBT recycle streams.
There accordingly remains a need for further improvement in the properties of PBT-polyamide blends. There especially remains a need to improve the compatibility of PBT-polyamide blends, in order to provide improved mechanical properties and bonding to other polymers. It would further be advantageous to improve the surface delamination observed in PBT-polymer blends. It would also be advantageous if the PBT used in such blends could be derived from a renewable or recycled source, such as scrap polyethylene terephthalate (PET).